Non-rotary cutting single edged knifes for trimming paper products are known. These prior art knives are single edged and are typically affixed to industrial cutting machines that operate in a reciprocating fashion. A draw back of these single edged knives is that they cause damage to soft cover bindings when trimmed. This damage typically manifests itself as small areas of backbone chipping/tearing that greatly diminishes the quality of the binding, which can ruin the visual appearance of the finished product. Prior art backbone trimming knives dull quickly and require multiple change outs resulting in production loss time of from 30 to 60 minutes. With typical machinery producing anywhere between 8,000 to 30,000 books per hour, frequent change outs are very costly.
Accordingly, there exists a strong need to provide an improved knife design that avoids damage to the binding, provides a clean visually appealing trimmed edge, and maintains its cutting edge, thus avoiding costly frequent change outs. The present invention achieves this goal and overcomes the above-mentioned problems by providing a combination of a primary blade with at least one beveled edge backbone blade where the cutting edge is offset from (i.e. angled relative to) the primary cutting edge.
These and other advantages of the invention will become evident from the following more detailed description of the invention.